Patent AU-2015275302-A1 (AU)
Title: Method and apparatus of determining stiffness coefficients of formation
Inventor: LIU ZHONGHUA
IPC: E21B49/00
Filed: 2015-12-23
Abstract: The present invention proposes a method and apparatus of determining stiffness coefficients of formation, wherein the method comprising: depending on stiffness 5 coefficients of a formation core sample, setting up a relation of stiffness coefficients of formation C11 and C33 , C4 , C66; depending on formation logging information, computing clay content of formation along depth continuously; depending on a P-wave velocity and a volume density of the formation, computing the stiffness coefficient of formation C33 along depth continuously; depending on a S-wave velocity and a 10 volume density of the formation, computing the stiffness coefficient of formation C4 along depth continuously; and then depending on the calculations above, the relation of stiffness coefficients of formation C11 and C33, C4, C66, and a relation of an anisotropy coefficient of the P-wave of the formation and its clay content or a relation of an anisotropy coefficient of the S-wave of the formation and its clay content, 15 computing the stiffness coefficients of formation C11 and C66 along depth continuously. The present invention does not need to calculate stiffness coefficients by using a horizontal S-wave velocity inversed from the extracted stoneley waves, and avoids an extraction process of horizontal S-wave, such that the calculation is simple and effective. 7262424_1 (GHMatters) P101911.AU conducting an acoustic anisotropy measurement and a volume density calculation for a core sample, obtaining stiffness 101 coefficients and an anisotropy coefficient of P-wave and S-wave of the core sample conducting an X diffraction measurement for the core sample, obtaining the clay content data thereof setting up an experimental relation of an anisotropy coefficient of P-wave of the core sample and its clay content, and an 103 experimental relation of an anisotropy coefficient of S-wave of the core sample and its clay content depending on the obtained stiffness coefficients of the core 104 sample, setting up a relation of stiffness coefficients Clicore and C33core , C44core ,C66core utilizing conventional logging information of target layers of target 105 wells, computing the clay content of formation in target layers along depth continuously utilizing the P-wave and S-wave velocity and volume density well logging curves of the target layers of the target wells, computing 106 stiffness coefficients of formation C33formation and C44ormation and in target layers along depth continuously depending on the relation of the anisotropy coefficient of P-wave of the core sample and its clay content, the clay content of the formation and the stiffness coefficient of the formation C33formation, computing the stiffness coefficient of the formation Cliformation along depth continuously; depending on the relation of the 107 stiffness coefficients of the core sample Clicore and C33core , C44core ,C66core and the stiffness coefficients of the formation C33formation, C44formation and Cliformation, computing the stiffness coefficient of the formation C66formation along depth continuously; alternatively, depending on the relation of the anisotropy coefficient of S-wave of the core sample and its clay content, the clay content of the formation and the stiffness coefficient of the formation C44formation, computing the stiffness coefficient of the formation C66formation along depth continuously, depending on a relation of the stiffness coefficients of water-saturated core sample Clicore and C33core , C44core ,C66core, the stiffness coefficients of the formation C33formation, C44formation and C66formation, computing the stiffness coefficient of the formation Cliformation along depth continuously Fig. 1